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Burns 219

the burn wound is large and full-thickness. The major disadvantage is cost of the graft as well as its interference with the physical therapy
performing a major operation, with potential for a lot of blood loss, on a programme (after grafting, the patient has to be immobilised for 7–10
very sick patient, as well as the fact that it does not appear to materially days), easy traumatisation and blistering, breakdown, and lack of long-
change the pattern of the causes of death in those who die after 3 days of term durability because of the abnormal histologic architecture.
hospitalisation. Due to a lack of resources, in many hospitals in Africa, Complications
the eschar is often allowed to separate on its own, leading to an increased
risk of infections and prolonged convalescence. Complications after a burn injury may be examined from different
perspectives. A thorough knowledge of the potential complications
Wound Closure on initial evaluation and admission of the child allows the physician
Biologic dressing and biosynthetic products to prevent those complications. Acutely, the most feared complication
Following spontaneous eschar separation or, preferably, after surgical is death. Others are complications related to the burn injury itself and
removal by tangential or fascial excision, extensive wounds can be per- subsequent organ failure, including death.
manently covered with autograft or temporarily covered using a variety Burn complications may be classified as infective and noninfective.
of techniques and dressings. Infective Complications
Biologic dressings, such as porcine xenograft or cadaveric allograft, Infection is the most common and most serious complication of a major
are most commonly used. These provide early temporary wound burn injury. Sepsis accounts for 50–60% of deaths in burn patients
closure, and therefore contribute to the prevention and control of today despite improvements in antimicrobial therapies. Infections
infection, the preservation of healthy granulation tissue, and the include bronchopneumonia, pyelonephritis, thrombophlebitis, and
maintenance of joint function. They decrease evaporative water loss invasive wound infection.
and limit heat loss secondary to evaporation; they cover exposed Microbial colonisation of the open burn wounds, primarily from an
sensory nerves, and thus decrease pain associated with the open endogenous source, is usually established by the end of the first week.
wound; and they protect neurovascular tissue and tendons that would After a burn injury, in the absence of topical chemotherapy, the
otherwise be exposed. The major drawbacks are their variable quality superficial areas of the burn wound contain up to 10 organisms per
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and, depending on donor age and harvesting technique, both have to gram of burn tissue within 48 hours following the injury.
be removed and both carry potential risk for viral infection. Amniotic Routine administration of prophylactic antibiotics is associated
membranes have also been used. Tissue engineering and advancements with an increased incidence of yeast colonisation of the gastrointestinal
in biotechnology have provided several novel modalities to address tract and the rapid emergence of resistant gram-negative organisms in
those issues. Varieties of products are available, including skin, dermal, the burn wound, although antibiotics do not decrease the incidence of
and epithelial substitutes. early gram-positive cellulitis. Indeed, even a brief 5- to 7- day course
Biosynthetic products used for temporary wound closure include of prophylactic penicillin hastens the emergence of resistant gram-
Apigraf (allogeneic bilayered skin equivalent, which consists of negative organisms. The potential harm caused by widespread use
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human keratinocytes and human fibroblasts in a lattice of bovine type of prophylactic antibiotics has been known since the 1970s, but this
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I collagen); Biobrane (nylon mesh coated with porcine collagen type practice is still rampart in many African hospitals.
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I peptides and bonded to silicone rubber membrane); and TransCyte Antimicrobial therapy is directed by bacterial surveillance through
(human neonatal fibroblasts seeded on coated nylon of Biobrane). The routine tri-weekly sputum, urine, and wound cultures, and antibiotics
latter tissue substitute contains multiple growth factors and secreted should be given only to treat specific infections. For example, gram-
matrix molecules, and is not only effective in treatment as a temporary positive cellulitis caused by beta-haemolytic streptococci should be
closure of excised wound, it is also easy to handle and to remove with treated with penicillin. It is noteworthy that bacterial counts of <10
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reduced bleeding as compared to allograft. Its drawback, however, is a organisms/gm are not usually invasive and allow skin graft survival
significant cost of production. rates of >90%, without the use of antibiotics.
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Dermal substitutes include: Integra (bilaminate membrane, which Methods of diagnosis of burn wound infection include clinical
consists of bovine collagen–based dermal analogue covered with examination, quantitative cultures of a burn wound biopsy, and burn
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silastic sheeting); AlloDerm (an acellular dermal substitute from wound histology.
cryopreserved human cadaver skin that is deprived of cells of the Generic clinical signs of burn wound infection include any of the
epidermis and dermis, leaving dermal matrix and basement membrane); following:
and Matriderm (a bovine noncross-linked collagen/elastin matrix). • spreading peri-wound erythema;
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Definitive burn wound closure is the ultimate objective of all burn
wound care. However, priorities of coverage are dictated by functional • oedema and/or discoloration of unburned skin at wound margin
and cosmetic considerations. The hands, feet, face (especially the (usually due to Pseudomonas infections);
eyelids), neck, and joints should in general be covered prior to • rapid eschar separation (bacterial wound sepsis, may be fungal in
nonfunctional surfaces. some environments);
Cultured epithelium • punctuate haemorrhagic subeschar lesions;
The technique of cultured epithelium involves the tissue culture growth
of epidermal cells obtained from the prospective recipient, who will • conversion of partial-thickness burns to full-thickness wounds;
require grafting. Often, patients with extensive thermal injury have a • black or brown patches of wound discoloration;
disparity between available donor sites and the areas requiring cover-
age. Additionally, due to the paucity of donor sites, multiple graft • green pigment (pyocyanin) visible in subcutaneous fat
harvests from the uninjured areas may be necessary, yielding tissue of (Pseudomonas infection);
progressively inferior quality. Cultured autologous keratinocytes have • ecthyma gangrenosa—violaceous or black, erythematous nodular
been used successfully to cover patients with massive skin defects lesions in unburned skin (typically progress to focal necrosis);
secondary to burn injury. • burn wound cellulitis;
Use of this technique in major burns may be the only way to prevent
major burn complications and the consequent contractures, but it is • invasive burn wound infection; and
not without its downsides. Disadvantages include the immensely high